Test Equipment Anonymous (TEA) group therapy thread

[med6753]

On the subject of food, this just out of the oven: one tarte tatin. Ingredients: flour, butter, apples, sugar, water, that is all.



(The colour balance is a bit off but I can't be arsed to fix it.)

No fair. You just made my blood sugar jump by 30 points. 

[Neomys Sapiens]

[
mnem
   

Get a proper one:

Pffft, that's not a proper one! THIS is a proper one:

[Vince]

The EMEX organisers felt very sorry for me having to spend three days in close confinement with tautech in the Siglent booth. So they gave me my own booth!!!

Of course being the upstanding gentleman I am, I let him use it....

It then begs the question : how did you manage to get the booth of the guy next to you ? Did you kill him ? Did he never show up, he canceled and the organizers let you have his space ?!
You got it for free or did you have to pay double ?! 

Single booth space was a bit small... but double space looks a bit large now.... needs something in between, one and a half booth...

[vk6zgo]

Please refrain from posting picture of my sister 

Oh that's cruel.  Ex-wives are fair game but not your sister. Have a heart. 

Ex wives are less likely to "snot you one" for being a cheeky little turd!

[vk6zgo]

I was unhappy with the results I was getting testing the resistance across the banana plugs on that last design, they were very inconsistent, between about 80 microohms and 4 milliohms. I seriously doubt the credibility of the 80 microohms reading, I think I'm getting noise from the TE effect between the plug and wire, and some inconsistent contact also.

So I changed tack, and decided to make a short using only copper:



This is far superior. It measures consistently 2.35 to 2.40 milliohms "plug" to "plug". I tweaked the "plugs" for a gentle fit into a 4mm socket, it works well.


EDIT: The inductance between plugs measures <20nH, which is basically in the noise as far as this LCR meter is concerned.

Sorry if this is being stupid... why not simply take an oxy-acetylene torch and melt / fuse the 4 copper wires together ? That would make for a reliable and low impedance connection wouldn't it, and no TE effect. Just.. a blob of copper. 

Sure, I could try that. Do you have a spare oxy-acetylene torch I can borrow?

It wouldn't work though. Heating the copper like that would make it oxidize badly. You could try using a flux to stop that happening of course, but that would introduce more chemicals to the mix, no problem if you're welding, but likely very problematic in this use case. Not to mention what the heat cycling is likely to do to the electrical properties of the piece.

I don't have a torch because I don't have a garage, but as soon as the garage is built my old man will give all his tools, so the oxy-acetylene gear will be part of it 
Oxidization hmmm... would that not be limited to the surface of the blob ? Was hoping the core of the blob would still be pure copper. OK well, too bad uh... so TIG welding with a shielding gas it is then !
OK, if you don't have a torch, you probably don't have a MIG never mind a TIG.... back to square one... I am trying my best !

So get a MIG with a a tank of gas so that next time you are better prepared !

You live in an apartment, no garage/workshop ? OK I give up !

Looking at you picture, I am not sure the crimp is doing much at all does it ? The wires are twisted over such a long distance that I guess the total contact area between them is what makes for the good connection rather than the crimp at the very end ?  I bet if you just remove/cut crimp, the shunt would still measure just as good !

I have an oxy torch in my shed, but I haven't used it for years, having packed it all up when my eyesight started to go to crap, along with the cost of hiring gas becoming prohibitive.

Since then, I have had my eyes fixed & there are less expensive ways of buying gas, so I have toyed with the idea of of reviving it, but would have to buy "spark arrestors" which are quite expensive. ----millions of people used Oxy-acetylene gear for decades without them, but that is now in the  category!

Don't get me wrong, they are a good idea, but it would be nice if they were just a bit cheaper!

[mnementh]

https://www.harborfreight.com/240v-spot-welder-61206.html?ccdenc=eyJjb2RlIjoiODkwNjEzMzUiLCJza3UiOiI2MTIwNiIsImlzIjoiMTMxLjI0MjUifQ%3D%3D

Seems to me like a good excuse to get one-a-deez... 

mnem
Just need to fab up some stainless points to keep it from sticking...

[mnementh]

Please refrain from posting picture of my sister 

Oh that's cruel.  Ex-wives are fair game but not your sister. Have a heart. 

Ex wives are less likely to "snot you one" for being a cheeky little turd!

In some cases exes will snog you silly, if your delivery is just right... 

mnem
twitch... twitch... twitcha-twitch...

[tautech]

The EMEX organisers felt very sorry for me having to spend three days in close confinement with tautech in the Siglent booth. So they gave me my own booth!!!

Of course being the upstanding gentleman I am, I let him use it....

It then begs the question : how did you manage to get the booth of the guy next to you ? Did you kill him ? Did he never show up, he canceled and the organizers let you have his space ?!
You got it for free or did you have to pay double ?! 

Single booth space was a bit small... but double space looks a bit large now.... needs something in between, one and a half booth...

Exhibitor next to us was a “no show” so rather than have the booth next to us empty the organisers offered it to us free. 
The tautech is very pleased and is organising a 2nd large table and more of his gear to exhibit tomorrow.

[med6753]

Skip to 6 minutes and listen to what he says about putting capacitors in parallel. 


Yes, he got called on it in the comments.

[Cubdriver]

He got his series and parallel caps mixed up...  Oops!

-Pat

[Cubdriver]

Interesting that it has the flat CRT bezel and what looks like an aluminum handle, whereas the one I recently got has a protruding bezel and a rubber/vinyl handle.  Both appear to be straight 321s, not As.



-Pat

[med6753]

Yup. My "A" is the same as yours. Apparently was a late production change.

[Cubdriver]

Something I just noticed between your A and my plain one is that yours has the pull for X5 magnification marked on the knob, and mine has a plain knob with the marking on the front panel.  Probably because they changed the power switch from a toggle to a rotary and didn't have the space for the marking on the panel.  Interesting to see the subtle changes they went through as they evolved.

Edit to add - and yours also has a ground position on the input coupling switch and a low battery indicator light.

-Pat

[mansaxel]

Not to mention what the heat cycling is likely to do to the electrical properties of the piece.

You are allowed to fix it in something else than the meter while brazing it, I suppose? 

[mansaxel]

Get a proper one:

That's a nice one.

I'm doing some research on rebuilding my pool water treatment system with a variable frequency drive for the main pump. There are Danfoss ones that have pump control programs built-in, so can, given a pressure reading,  maintain pressure downstream from the pump properly under various conditions. Also alarm handling et al is built-in, which would safeguard from low water incidents, whether from leaks or clogged skimmer and similar.

Now these aren't cheap, but there's an used market, mostly in Germany. I from time to time make sweeps of relevant Ebay categories.

[mansaxel]

Pffft, that's not a proper one! THIS is a proper one:

The forklift holes are a nice touch.

[Robert763]

[
mnem
   

Get a proper one:

I recently got a medium sized one 
A used Toshiba 400W (1kVA) "TOSVERT"  VF-nC3 single phase in 3 phase out varable frequency drive and a 1/2 hp 6 pole TEFC motor to put on my ancient Myford lathe.
The VFD was useed complete with a wireless gate controller - £20 and the motor is new old stock sealled in the box for £50. Six pole motors are a bit unusual but as the Myford is fairly low speed It means I can do without a layshaft and get even smoother running than a 4 pole motor.  The motor is inverter rated and the VFD has vector control so should be quite a good set up. Just need to get it installed. Might do it as a break to the garage re-organisation as I have lots of room at the moment.
 

[bd139]

Pffft, that's not a proper one! THIS is a proper one:

The forklift holes are a nice touch.

Everything can have forklift holes from experience 

[Robert763]

Get a proper one:

That's a nice one.

I'm doing some research on rebuilding my pool water treatment system with a variable frequency drive for the main pump. There are Danfoss ones that have pump control programs built-in, so can, given a pressure reading,  maintain pressure downstream from the pump properly under various conditions. Also alarm handling et al is built-in, which would safeguard from low water incidents, whether from leaks or clogged skimmer and similar.

Now these aren't cheap, but there's an used market, mostly in Germany. I from time to time make sweeps of relevant Ebay categories.

I didn't read this before my lathe post... The little TOSVERT has a PID controller built in so it will do all this. Maybe look at a more generic one rather than pump specific?

[mansaxel]

The forklift holes are a nice touch.

Everything can have forklift holes from experience 

The Cisco 12016 chassis with a forklift hole where the switch fabric and clock scheduler card cage usually sits was a nice touch. Slightly expensive, though. The chassis is practically free; the line and fabric cards carry the cost.

[Robert763]

Pffft, that's not a proper one! THIS is a proper one:

The forklift holes are a nice touch.

Everything can have forklift holes from experience 

Only if object largest dimension > tine width

[bd139]

The forklift holes are a nice touch.

Everything can have forklift holes from experience 

The Cisco 12016 chassis with a forklift hole where the switch fabric and clock scheduler card cage usually sits was a nice touch. Slightly expensive, though. The chassis is practically free; the line and fabric cards carry the cost.

I refer in my case to the forking good job some pallet monkeys did to an HP DL580 G9. Literally impaled the poor thing through the box, packaging and fan tray. In an effort to hide this and blame it on someone else they cling wrapped the entire pallet and chucked it on the truck.

"Hey Phil, do you recognise the shape of that hole?"

"Ah yes, it's the greater spotted fuckwit's pecker hole"

[capt bullshot]

I'm doing some research on rebuilding my pool water treatment system with a variable frequency drive for the main pump. There are Danfoss ones that have pump control programs built-in, so can, given a pressure reading,  maintain pressure downstream from the pump properly under various conditions. Also alarm handling et al is built-in, which would safeguard from low water incidents, whether from leaks or clogged skimmer and similar.

Now these aren't cheap, but there's an used market, mostly in Germany. I from time to time make sweeps of relevant Ebay categories.

I've got a pump similar to this one in the central heating system:
https://product-selection.grundfos.com/de/products/alpha/alpha1?tab=models

I guess these are cost optimized to the max - they claim it has a control loop for differential pressure, but I think there isn't any pressure sensor at all. IMO they use the realationship of differential pressure to motor torque to motor current to determine their operating point. Don't know if one of these would be appropriate for your needs. I'd guess it's substantial less cost than a solution made of components.

[McBryce]

Pffft, that's not a proper one! THIS is a proper one:

The forklift holes are a nice touch.

Everything can have forklift holes from experience 

Yes, they can always be added later....

McBryce.

[Neper]

I'm doing some research on rebuilding my pool water treatment system with a variable frequency drive for the main pump.

A pool? For ice skating?